package db9;

public class PanDuanNull {
    String m=null;
    String n=null;
    public static void PanDuanNull(String m,String n) throws NullPointerException{

            if (m==null){
                throw new NullPointerException();
            }
            if(n==null){
                throw new NullPointerException();
            }
        }

    public static void main(String[] args) {
        String m=null;
        String n=null;
        try {
            PanDuanNull(m,n);
        }catch (NullPointerException e){
            e.printStackTrace();
        }
    }
    }
